Process for making sail release synthetic textile



United States Patent 3,535,141 PROCESS FOR MAKING SAIL RELEASE SYNTHETIC TEXTILE Francis W. Marco, Spartanburg, S.C., assignor to Deering Milliken Research Corporation, Spartanburg, S.C., a corporation of Delaware No Drawing. Filed Apr. 17, 1967, Ser. No. 631,149 Int. Cl. B32b 27/30; B44d 1/092 U.S. Cl. 11747 18 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The textile industry during the past decade has, as a whole, made important technological advances in the chemical finishing of textile fabrics. Numerous processes have been developed for imparting minimum care characteristics to garments and articles prepared from specially treated textile fabrics. Exemplary of such advances are the wash and wear fabrics, hereinafter referred to as precured fabrics, and the durable press fabrics, hereinafter referred to as post cured fabrics. These characteristics generally have been imparted to textile fabrics by the application of resinous materials. The resinous materials are applied to the fabric and are later crosslinked to the fabric by the action of a suitable catalyst. Depending upon the time at which the crosslinking reaction occurs, either a wash and wear fabric or a durable press fabric is produced. The precured fabrics are those for which the crosslinking reaction has occurred prior to transformation of the fabric into a garment or other article of commerce. Post cured fabrics are those fabrics which are subjected to the crosslinking reaction subsequent to the transformation of the fabric into a garment or other article of commerce.

Tremendous effort has ensued towards achievement of a garment containing synthetic and naturally occurring fibers such that creases in the garment are very durable and are appreciably affected by wear or cleaning processes. In other words, after repeated washings and/or dry cleaning, the creases remain in the garment in a substantially unaltered condition and further treatment of the garment, i.e., pressing, is not required for maintenance of the crease. Likewise, much effort has been expended towards the attainment of good wash-and-wear fabric.

Additionally, further research has been directed to the attainment of a garment having improved soil release properties. Numerous of the synthetically produced fibers that are presently being incorporated in blends with naturally occurring fibers have a propensity to accept and retain oily grime and dirt. Accordingly, when the garment is being worn the soil and/or oily materials accumulate on the garment and settle in the fabric. Once the garment becomes soiled, it is then subjected to a cleaning process for removal of the dirt and/or oily deposits, and only a dry cleaning process will successfully clean the garment.

The cleaning process normally employed, however, is washing in a conventional home washing machine by the housewife. During a wash cycle, it is virtually impossible to remove the soil and/ or oily stains from the garment and, secondly, assuming that the undesirable materials are removed from the garment or a fairly clean garment is being washed, soil remaining in the wash water is redeposited onto the garment prior to the end of the wash cycle. Hence, when the garment is removed from the washing machine and subsequently dried, it has not been properly cleaned. Such a condition, heretofore unavoidable, is quite disadvantageous in that the garment after being worn never again assumes a truly clean appearance, but instead tends to gray and/or yellow due to the soil and/or oily materials deposited and remaining thereon. Further use and washing of the garment increases the intensity of the graying to the point that ultimately the garment is unacceptable for further wear due to its discoloration. The process of the present invention solves the soiling problem as hereafter described.

In attempting to solve the problem of soiling in the synthetic fabrics and blends containing synthetic fabrics, a substantial amount of research has been conducted and numerous patents have issued as a result thereof. None of these patents, however, disclose subject matter as relevant to the problem as is instantly set forth herein. Strong basis of this fact is evidenced by the absence from the market of a product that may be easily cleaned so as to remove soil and alleviate redeposition of soil from the wash water. Anti-soiling research has been directed along two general avenues, one of which utilizes inorganic materials and the second employing the utilization of organic materials. Set forth below is a brief summary of prior efforts.

U.S. Pat. 2,999,774 to Schappel features the utilization of silica particles and a salt of a multivalent metal for the purpose of rendering a fabric soil resistant. U.S. Pat. 2,734,835 to Florio et al. employs at least two hydrous stable metal oxides selected from aluminum, silica, titanium, beryllium, cerium, cobalt, germanium, manganese, tin, zinc and zirconium. U.S. Pat. 3,089,778 to Pierce et al. teaches the utilization of a water insoluble basic aluminum salt having an ultimate particle size of less than 0.5 micron. U.S. Pat. 2,992,943 to Coover et a1. while not purely related to inorganic materials is directed to prevention of dry soiling only. In other words, the Coover et al. treatment dictates the use of a water-soluble compound (an alkyl titanate and an organic solvent) and therefore to obtain the desired soil resistant properties only a dry cleaning process may be employed.

The organic approach to the soiling problem of synthetic fiber containing fabrics includes the following patents and their teachings. It should be noted, however, that some of the patents incorporated in the following group are not per se directed to reducing the soiling propensity of the synthetic fiber containing fabric.

U.S. Pat. 3,236,685 to Caldwell et al. renders a fabric antistatic and soil-resistant by coating a fabric with a solution or solutions containing a polymeric acid defined as containing COOH, SO H and/ or PO H groups. Additionally, a compound containing a polyol or a compound having incorporated therein epoxide groups is included which under proper conditions reacts with the acid to form an ester. U.S. Pat. 3,152,920 also to Caldwell et al. is a complement of the above patent wherein, instead of reacting the polymeric acid with a polyol or an epoxide, the polymeric acid is reacted with the reaction product of a polyol and a polyisocyanate. U.S. Pat. 3,125,405 to Gordon is directed to the manufacture of a permanent press garment. N methylol acrylamide is applied to the fabric with a free radical acid catalyst and the N-methylol acrylamide is cross-linked with the cellulose molecule. Additionally, extra monomers and polymers as set forth in the patent may be incorporated in the treating solution. U.S. Pat. 3,246,946 to Gordon likewise is directed to the production of durable press garments. N-1nethylol acrylamide is employed in conjunction with one or more condensates of an aldehyde and a free radical acid catalyst whereby the reactants are crosslinked with the cellulose molecule. Extra monomers and polymers may be added to the treating solution. U.S. Pat. 3,090,704 to Collins et a1. is directed to a terpolymer for rendering the fabric soil resistant. The terpolymer consists of (1) a compound having incorporated therein a crosslinking component, (2) a compound having incorporated therein an anionic component, e.g., an alkali metal salt of an aromatic sulfonic acid, and (3) a compound having a component therein that contains a strong nonionizable, nonhydratable permanent or induced dipole. U.S. Pat. 2,876,141 to Matthews employs a solution containing (1) mineral oil, (2) base Cordage oil, (3) oleic acid, and (4) a cationic wetting agent, e.g., trimethyl-fi-oleamidoethyl ammonium sulfate in an effort to improve the soil resistance of the fabric treated.

The above brief abstracts are set forth to provide an indication of prior research effort directed to attaining a soil resistant fabric or a fabric having soil release properties. The problem heretofore confronted with fabrics including synthetic fibers has been that the synthetic fibers while hydrophobic are oleophilic and whereas oil and grime may become embedded in the fiber, its hydrophobic properties prevent water from entering the fiber to remove the contaminants therefrom. The efforts of this invention have been directed to the modification of the properties of synthetic and/or natural fibers in such a manner that the soil and oily contaminants may be easily removed.

Additionally, by incorporating the process of the present invention with that of a process to render a garment resistant to creasing, a garment is produced that has both durable press and soil release properties. In other words, the ultimate garment is superior both for the consumer and for the housewife who is confronted with the problem of rendering the garment clean for further wearing.

In view of the above comments, it should be evident to one skilled in the art that the problem confronted has been that of rendering a garment clean if the garment contains synethtic and/ or natural fibers as described herein. Accordingly, by virtue of the teachings of the present invention, the problems historically present with the use of garments having incorporated therein both cellulosic fibers and synthetically produced fibers are alleviated.

It is therefore an object of the present invention to provide a substrate having improved soil release properties.

Still another object of the present invention is to provide a process for treating textile material whereby said material easily releases soil when contacted with a detergent solution.

Still further another object of the present invention is to treat a synthetic polymeric textile material in such a manner that after said material is soiled and subjected to washing, less soil and grime from the Wash water will be redeposited thereon.

A further object of the present invention is to provide a durable press fabric having improved soil-release properties.

Another object of the present invention is to provide a process for treating a fabric in such a manner that it has both durable press and soil release properties.

Still another object of the present invention is to treat fabric including synthetic polymeric fibers in such a manner that after a garment produced therefrom is soiled and subjected to washing, soil and grime from the wash water will not be redeposited onto the garment.

Still further another object of the present invention is to provide a treatment for fabric such that garments produced therefrom will not become discolored due to repeated wearing and washing.

Still further another object of the present invention is to provide a treatment for fabric such that garments produced therefrom will not become discolored due to repeated wearing and washing.

A further object of the invention is to provide a fabric including synthetic polymeric fibers which has improved soil release characteristics.

An additional object of the invention is to provide a fabric including synthetic polymeric fibers which has improved soil release characteristics and also durable press and/or wash and wear characteristics.

SUMMARY OF THE INVENTION In accordance with the present invention, soil release characteristics are imparted to a synthetic polymeric textile material by a process which comprises subjecting the textile material to an alkali and applying to the textile material a soil release polymer. Preferably, the textile material is subjected to textile resin curing conditions. Advantageously, a textile resin and a textile resin catalyst also are applied to the textile material.

The process of the present invention may be used to treat a wide variety of textile materials made exclusively from synthetic polymeric fibers, as well as blends of natural and synthetic fibers. Examples of synthetic fibers which may be successfully employed in the practice of the present invention include those made with polyamide, acrylic and particularly polyester fibers, i.e., various types of Dacron, a registered trademark of E. I. du Pont; Fortrel, a registered trademark of Celanese; Kodel, a registered trademark of Eastman Kodak, etc. Blends of natural and synthetic fibers which may be utilized to prepare fabrics according to the present process include fabrics comprising polyester and 50% cotton; polyester and 35% cotton; etc. Cellulosic fibers, for example, cotton, viscose, regenerated cellulose, etc., also may be combined with the synthetic fibers.

The alkali to which the synthetic polymeric textile material is subjected in accordance with the invention may be an alkali metal hydroxide, an alkali metal salt, etc., and particularly a hydroxide of sodium, potassium or lithium. While it is known to treat cellulosic materials with an alkali, for example, mercerization, the treatment of synthetic polymeric textile materials with alkali has been considered to be detrimental because of the deleterious effects produced, e.g., loss of strength. However, in accordance with thepresent invention it has been discovered that subjecting a synthetic polymeric textile material to treatment with the alkali and thereafter applying a soil release polymer provides an unexpected improvement in the soil release characteristics of the textile material.

The alkali is generally employed as an aqueous solution. The proportion of the alkali may be varied over a wide range, for example, between about 0.1% and the limits of solubility, and particularly between about 0.25% and 25% by weight. The concentration of the alkali, to an extent, depends upon the duration of the treatment and the temperature thereof, with lower concentrations being particularly useful with elevated temperatures and longer treatment times. The temperature of the solution may vary from ambient temperatures or below up to the boiling point of the alkali solution. The treating period may vary in length from less than a minute up to several hours or more and preferably, 0.1 to 30 minutes. The alkali treatment may be performed on the textile material as part of the normal preparation of the material, i.e., the scouring, bleaching, etc., or may be performed prior to or subsequent to the fabric preparation operations.

The term textile resin according to the present invention includes both monomers and polymers which when applied to a textile material and reacted under proper conditions undergo polymerization and/or condensation and are transformed to the thermoset state. Textile resins that may be employed when practicing the present invention include epoxy, acetal, aminoplast resins, etc., with the aminoplast resins being preferred. These nitrogen containing resins when applied to a textile material in the presence of a catalyst at temperatures of from 100 C. to about 300 C. are transformed into the thermoset state. The aminoplast resin condenses with the cellulose molecules and when vinyl groups are present in the aminoplast resin, it undergoes addition polymerization with itself and also with the cellulose molecule if irradiated. The cured textile resin on the textile material afiords the textile material a durable press and/or wrinkle resistant characteristic Exemplary of the aminoplast resins that may be employed according to the present invention are the urea formaldehydes, e.g., propylene urea formaldehyde, dimethylol urea formaldehyde, etc.; melamine formaldehydes, e.g., tetramethylol melamines, pentamethylol melamines, etc.; ethylene ureas, e.g., dimethylol ethylene urea, dihydroxy dimethylol ethylene urea, ethylene urea formaldehyde, hydroxy ethylene urea formaldehyde, etc., carbamates, e.g., alkyl carbamate formaldehydes, etc.; formaldehyde-acrolein condensation products; formaldehyde-acetone condensation products; alkylol amides, e.g., methylol formamide, methylol acetamide, etc.; acrylamides, e.g., N-methylol acrylamide, N-methylol methacrylamide, N-methylol-N-methacrylamide, N-methylmethylolacrylamide, N-methylol methylene-bis-(acrylamide), methylene-bis-(N-methylol acrylamide), etc.; haloethylene acrylamide; diureas, e.g., trimethylol acetylene diurea, tetramethylol-acetylene diurea, etc.; triazones, e.g., dimethylol-N-ethyl triazone, N-N-ethylene-bis-dimethylol triazone, halotriazones, etc.; haloacetamides, e.g., N- methylol-N-methylchloroacetamide, etc.; urons, e.g. dimethylol uron, dihydroxy dimethylol uron, etc., and the like. Mixtures of aminoplast textile resins are also within the scope of the present invention.

Further exemplary of the textile resins within the scope of the present invention are those which conform to the following structural formulae. In each of the following formulae the variables may be selected as follows:

R hydrogen, lower alkyl or residue of saturated or unsaturated aldehyde R hydrogen, lower alkyl or CXCR -CHR R hydrogen or methyl R hydrogen or lower alkyl R hydrogen, lower alkyl, or CHR OR at least one R being CHR OR R lower alkyl or hydroxy alkyl R hydrogen, hydroxyl or lower alkyl R hydrogen, lower alkyl, alkylol or alkenol X: sulfur or oxygen and where may have substituted therefore or sulfonium if desired.

R 0OHR -NR CGR =CHR where a is a whole integer from 1 to 6 The amount of the textile resin employed is primarily determined by the ultimate use of garments or articles prepared from the fabric. Very small amounts of the resin will afford some improvement and large amounts even greater improvements, but the larger amounts of resin generally adversely affect the hand of the fabric. Hence, the amount of resin employed is preferably that which will afford good crease retentions and flat dry properties while not adversely affecting the hand. For the purposes of the present invention, the amount of textile resin in the pad bath may vary between about 2 and 30% by weight. Resin applied to the fabric should be in the range of about 2 to 20% based on the dry weight of the fabric and preferably in the range of about 4 to 9% Catalysts employed within the scope of the present invention depend upon the specific textile resin that is applied to the textile material. For instance, if the textile resin has a functional group that is reactive under acidic conditions, then an acid catalyst is used. Likewise, when a functional group is present that is reactive under alkaline conditions, then a base catalyst is used. Furthermore, both acid and base catalysts may be used when both types of functional groups are present in the textile resin. In this instance, the catalyst may be added separately or together. When they are added together, one must be a latent catalyst, i.e., one that will not initiate its reaction during the opposite type reaction, but may be activated subsequently under proper catalytic conditions.

The catalysts useful in activating the acid or base reactive groups are those conventionally used to activate the reaction of textile resins containing the same group for reaction with hydroxy groups of cellulose. Preferably, latent acid or base acting catalysts are utilized, that is compounds which are acidic or basic in character under the curing conditions. The most common acid acting catalysts are the metal salts, for example, magnesium chloride, zinc nitrate and zinc fluoroborate and the amino salts, for example, monoethanolamine hydrochloride and 2-amino-2- methyl-propanol nitrate.

The basic acting catalyst preferably is a compound which does not initiate substantial reaction between the base reactive group and hydroxy groups of cellulose under normal acid conditions, but does initiate substantial reaction under prescribed conditions, such as elevated temperature or some other activating means, as through use of another chemical compound. For example, an alkali metal sulfite can be padded onto the fabric and be decomposed into strongly basic alkali metal hydroxide by including small amounts of formaldehyde in the steam used for curing.

The latent base acting catalyst utilized herein preferably comprises alkali-metal salts, such as alkali-metal carbonates like sodium carbonate, which is neutral to mildly alkaline, for example, pH of about 8.5 on the fabric but decomposes at temperatures in excess of about 80 C. to form the stronger base sodium oxide which will initiate substantial reaction at the elevated temperatures utilized during curing. Sodium carbonate may be utilized if desired since the pH in the fabric produced by this compound in normal conditions is generally insufficient to initiate the desired degree of reaction under normal temperature conditions.

If fabrics containing a base reactive group are maintained at pH levels above about 10, however, degradation occurs, so that essentially neutral or mildly catalysts are preferred when base reactive compounds are utilized.

Additional base acting catalysts include potassium bicarbonate, potassium carbonate, sodium silicate, alkali metal phosphates, such as sodium or potassium phosphates, barium carbonate, quaternary ammonium hydroxides and carbonates, for example, lauryl trimethyl ammonium hydroxides and carbonates and the like.

The amount of catalyst to be utilized is that conventionally used in activating the reaction between textile resins and hydroxy groups of cellulose, for example, up to about by weight of an acid acting catalyst in the application bath with the preferred range being from about 1% to about 7%. A preferred range for the base acting catalyst is again the conventional amount and is generally between about 0.2% to about 16%, preferably about 2 to 16%. The amount of catalyst is be utilized will further depend in part on the temperature at which the reaction is conducted and the amount of catalyst consumed in the reaction. For example, when base catalysts are utilized and if a highly acidic group is released during the reaction, the amount of base applied to the textile material should be at least sufficient to provide an excess of base in addition to that which is consumed by the highly acidic group.

The term soil release in accordance with the present invention refers to the ability of the fabric to be washed or otherwise treated to remove soil and/or oily materials that have come into contact with said material. The present invention does not per se prevent the attachment of soil or oily materials to the fabric, but hinders such attachment and renders the heretofore uncleanable fabric now susceptible to a successful cleaning operation. While the theory is still somewhat of a mystery, soiled, treated fabric when immersed in the detergent containing wash water experiences an agglomeration of the oil at the fabric surface. This water is basic in nature and it has been determined that soil release is best realized in wash water that is basic in nature. These globules of oil are then removed from the fabric and rise to the surface of the wash water. This phenomenon takes place in the home washer during continued agitation, but the same effect has been observed even under static conditions. In other words, a strip of polyester/ cotton fabric treated according to the process of the present invention and soiled with crude oil, when simply immersed in a detergent solution will lose the oil without agitation. The oil just balls up on the fabric, dislodges therefrom and rises to the surface of the solution.

An added feature of the present invention is the prevention of soil redeposition from the wash water. One of the greatest disadvantages of the synthetic polymers is the feature that even after removing the soil by washing, there is the continued danger that the soil will be redeposited onto the fibers from the wash water before the garment is removed therefrom. It has been observed that the soil releasability of the presently treated fabric diminishes after repeated washings. Even after the ability to remove soil from the fabric has diminished, however, the observation has been made that the prevention of redeposition of soil from wash water remains potent. This phenomenon likewise is unexplainable, but it has been established that the troublesome soil is negatively charged and presumably there remains enough acid on the :fabric to repel the negatively charged soil.

Some of the textile materials that may be treated according to the process of the present invention may not be feasibly removed from their environment and washed in a washing machine, e.g., upholstery fabrics. Further, there are also materials that may be treated which when subjected to the action of a washing machine are adversely affected either in structure or in looks. Articles within these classes may still be easily cleaned in place or otherwise by scrubbing the soiled area lightly with a solution of a commercial detergent and water.

The soil release polymer of the present invention may be selected from a large number of different compounds, for example, acid polymers, low molecular weight polyesters, polymerizable monomers thereof for in situ formation of the polymer, etc. The polymer employed advantageously is capable of forming a film around the fibers that constitute the textile material. Softness of the film is desirable for if the film is too hard, the hand of the textile material may be adversely affected. Further the film preferably has hydrophilic properties and is at least partially insoluble in water. The film, if water soluble, would, of course, be easily washed from the fabric. The polymer from which the film is formed may, however, be water soluble if applied with a textile resin, for during the curing process, the polymer if water soluble, is transformed to a water insoluble film. Furthermore, when the polymer is applied to a textile material without a textile resin, it may likewise be water soluble if the substrate is such that the soil removal is only required once. An acid content of at least 10 weight percent acid calculated as acrylic acid in the soil release polymer from which the film is formed is desirable, and preferably at least 20 weight percent. It has further been observed that acid polymers that afford soil release have a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1, and that an air dried film cast therefrom has a water of imbibition of at least 89%.

Synthetically produced acid polymers within the scope of the present invention may be prepared from any of the polymerizable organic acids, i.e., those having reactive points of unsaturation, e.g., one of the acrylic acids. These polymers may be homopolymers of the acids, or interpolymers of an acid and other monomers coplymerizable therewith so long as at least 10 weight percent acid monomer is present in the polymer. Exemplary of polymerizable acids that may be used, are acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, cinnamic acid, polymerizable sulfonic acids,

polymerizable phosphoric acids, etc. Monomers that may be interpolymerized with the acids include any monomers capable of copolymerizing with the acids and which will not detrimentally affect the film-forming properties of the polymer. Suitable monomers include, esters of the above acids prepared by reacting the particular acid with an alkyl alcohol, e.g., acrylic esters such as ethyl acrylate, methyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylate, Z-ethylhexyl acrylate, butyl acrylate, etc. alkyl fumarates, maleates, crotonates, cinnamates, etc.; vinyl halides; monomers having vinylidene groups; e.g. styrene, acrylonitrile, methylstyrene; substituted vinyl monomers, e.g., chlorostyrene; butadiene, etc. In all of the polymers prepared from the above listed monomers, there should be at least 10 weight percent :acid calculated as acrylic acid. It should be noted that various mixtures of the above polymers will work according to the process of the present invention and hence should be considered within the scope of the present invention. Furthermore, salts of the acid polymers, e.g., sodium, potassium, lithium, ammonium, etc., will afford the desired soil release characteristics.

Examples of some of the synthetic acid polymers that may be used according to the present invention are polymerization products of:

ethyl acrylatezacrylic acid ethyl acrylate acrylic acid acrylamide butyl acrylate acrylic acid ethyl acrylate:methacrylic acid ethyl acrylatezitaconic acid methyl methacrylate acrylic acid 2-ethyl hexyl acrylatezacrylic acid acrylamide acrylic acid butyl acrylate acrylic acid: acrylamide ethyl acrylate:aciylic acid:N-methylol acrylamide ethyl acrylate acrylic acid styrene ethyl acrylatezacrylic acidzhydroxy propyl methacrylate ethyl acrylatezacrylic acidzdivinyl benzene ethyl acrylatesacrylic acid:allyl acrylamide ethyl acrylatezacrylic acid: glycidyl acrylate ethyl acrylate:itaconic acid ethyl acrylatezsodium styrene sulfonate ethyl acrylate:crotonic acid styrenezacrylic acid ethyl acrylatezacrylic acidzhydroxy ethyl methacrylate hydr'oxy ethyl methacrylatezacrylic acidzacrylamide butyl acrylatezethyl acrylate:acrylic acid and the like.

Some acid polymers work better than others, however, and these are preferred. Examples of the preferred acid polymers include (1) copolymers of an acrylic ester such as ethyl acrylate and an acrylic acid that are prepared by polymerizing a co-monomer mixture of from about 10 to 80 parts of the acrylate and about 20 to 90 parts of the acrylic acid and advantageously from about 50 to 80 parts of the acrylate and 20 to 50 parts of the acrylic acid; (2) copolymers of propyl or isopropyl acrylate and acrylic acid wherein the copolymers are prepared by polymerizing a monomer mixture of from about 40 to 57 parts propyl o-r isopropyl acrylate and about 43 to 60 parts of acrylic acid; (3) copolymers of butyl acrylate and acrylic acid prepared by polymerizing a co-monomer mixture of from about 30 to 70 parts butyl acrylate and about 70 to 30 parts of acrylic acid; (4) copolymers of 2-ethyl-hexylacrylate and acrylic acid prepared by polymerizing a comonomer mixture of from about 10 to 40 parts of 2-ethyl hexyl acrylate and about 60 to 90 parts of acrylic acid; (5) copolymers substantially identical to the ones listed above with the exception that methacrylic acid is substituted for acrylic acid and the esters are methacrylates instead of acrylates; (6) a copolymer of ethyl acrylate and itaconic acid prepared by polymerizing a monomer mixture comprising about 70 parts ethyl acrylate and about 30 parts itaconic acid; (7) copolymers of the acrylic acid set forth above wherein the acrylates are replaced by methacrylates; (8) a copolymer of acrylamide and acrylic acid prepared by polymerizing a monomer mixture comprising about 10 parts acrylamide and about parts acrylic acid; and (9) terpolymers comprising ethylacrylate, acrylic acid and acrylamide prepared from monomer mixtures of ethyl acrylate, at least 10 parts acrylic acid and up to 20 parts acrylamide. One commercial polymer that has performed very satisfactorily and therefore is among the preferred acid polymers is Acrysol ASE-75, an acrylic emulsion polymer sold by Rohm & Haas Philadelphia, Pa.

The acid polymers suitable for use in practicing the present invention form a hydrophilic film upon drying and afford soil release ability at that point. For unknown reasons, further treatments and/or ingredients Will enfiance the soil release ability of the substrate. If the substrate having the acid polymer thereon is subjected to textile resin curing conditions, the durability of the soil release ability is enhanced. Likewise, the presence of a textile resin catalyst during the textile resin curing conditions further improves soil release ability. Still further, the soil release finish is much more lasting on a substrate when the acid polymer is subjected to textile resin curing conditions in the presence of an aminoplast textile resin. It is known that the film covers the hydrophobic synthetic fiber contents of the textile material without any reaction therewith. What is not understood, however, is the durability of the soil release characteristic. While it is known that there is some reaction between the acid polymer and the textile resin, the reaction mechanism is very speculative. Furthermore, there may be some crosslinking between the cellulose molecules and the acid polymer or there may be just an enhanced physical bond between the textile resin and the acid polymer above and beyond their reactivity.

Soil release polymers, like the textile resin, give some improvement at very low levels on the fabric. Accordingly, as the amount of soil release polymer is increased, the ability of the fabric to release soil increases. Thus, the upper limit on the amount of soil release polymer is determined by economics and resulting adverse effects on the fabric, e.g., the hand of the fabric. Furthermore, practically speaking there is a set range of soil release polymer dictated by commercial success.

The acid polymers, as a general rule, are emulsion polymers containing varying amounts of solids, normally in the range of about 25 to 50 weight percent. The polymer emulsion should be present in the pad bath or other application medium in the range of about 2.5 to 40 Weight percent. Otherwise stated, there should be from about 0.25 to 15 weight percent of acid polymer solids applied to the substrate, based on dry weight, and preferably 1.0 to 7.5 weight percent.

The composition used to impregnate the textile material according to the present invention is not limited to including only the possible ingredients heretofore mentioned, e.g., textile resin, textile resin catalyst and soil release polymer. In addition, other ingredients may be employed such as, for example, emulsifying agents, wetting agents, softeners, etc., and numerous other compounds that enhance the physical characteristics of the fabric. The composition may be applied to the substrate in any suitable manner. For instance, padding of the solution onto fabric is preferred because of ease of operation at that particular stage of the development. The composition may be sprayed on as a liquid; the substrate may be dipped, etc.

In general, the applicator system is adjusted to provide from 30 to weight percent Wet pickup by the fabric from the pad bath. Preferably, however, it has been de termined that best results are obtained by providing a wet pickup of from 40 to 60 weight from the pad bath.

When the aminoplast textile resin is applied to the textile materials, along with the soil release polymer, they may be simultaneously applied from the same pad bath. Simultaneous application is not required though and beneficial results may be realized by first applying the soil release polymer followed by separate applications of the textile resin and curing of the textile resin. Insofar as separate application is concerned, however, where the textile resin is applied first and cured and the soil release polymer added separately thereafter, initial soil release ability is outstanding, but not nearly so durable as the simultaneous application or the separate addition where textile resin and soil release polymer all are present during curing of the textile resin.

According to the desires of the individual, and the dietates of the ultimate product, separate or simultaneous application of the textile resin and the soil release polymer may be employed, For instance, when treating a textile fabric which is to be converted into work clothes, it would be desirable to have as durable a finish as possible so that the soil release properties will be as long lasting as possible. In this situation, either a simultaneous addition or a separate addition where the soil release polymer is added first would be desired. On the other hand, where the ultimate article of manufacture is not one that will be washed or cleaned on a weekly basis, for instance, the desirable property might possibly be to have a very superior initial soil release property. An example would be upholstery for automobiles, seat covers, wall coverings, etc. For these items it may be more desirable to first apply the textile resin and separately after curing of the textile resin apply the soil release polymer or just apply the soil release polymer, etc., as described herein, if a textile resin is not desired. It must be emphasized, however, that under such conditions the soil release properties are less durable than those attained by the aforesaid simultaneous means of application.

Advantages afforded by the process of the present invention are available for textile materials treated in almost any form, e.g., fibers, yarns, threads, fabrics or the ultimate product, e.g., a garment, etc.

Garments made from the fabrics treated according to the process of the present invention require no additional steps than those normally required for the preparation of the conventional durable press garments. In other words, the garment may be folded and pressed on conventional equipment, for example, a Hoffman press, The pressing cycle utilized is standard in the industry and generally involves pressing of the garment for a short period of time, followed by a curing operation in an oven. Alternatively, the garment may be set in a desired configuration under hot, dry conditions, such as by hot pressing without steaming, for example, at temperatures of up to about 300 C. for as long as necessary to cure the resin.

In general, the textile resin may be selected from several general types. According to the type resin selected, one of the following processes may be generally followed to achieve the novel garments produced by the present invention. In each type procedure, the methods of application and order of application of textile resin, soil release polymer, catalysts, etc., may be varied as described supra.

Type I (1) Subject fabric to an alkali, rinse and dry. (2) Apply textile resin having one type functional group, textile resin catalyst, and soil release polymer to fabric.

(3) Dry fabric at temperature that is insufficient to initiate catalysis of the textile resin.

(4) Make garment from fabric.

(5) Press garment to produce creases where desired.

(6) Subject garment to temperature sufiicient to catalyze and cure the textile resin.

Type II (1) Subject fabric to an alkali, rinse and dry.

(2) Apply textile resin having more than one type of functional group, textile resin catalysts for each type functional group and soil release polymer to fabric.

(3) Subject fabric to conditions whereby one type of functional group reacts and remaining functional groups remain dormant.

(4) Prepare garment from the fabric.

(5 Press creases where desired in garment.

6) Subject garment to conditions whereby the remaining functional groups are reacted With cellulosic fibers included in the fabric.

Type III 1) Subject fabric to an alkali, rinse and dry.

(2) Apply textile resin having more than one type of functional group, one type being sites of ethylenic unsaturation, a textile resin catalyst and a soil release polymer to the fabric.

(3) Dry the fabric at temperatures such that the textile resin catalyst remains dormant.

(4) Subject the fabric to irradiation.

(5) Make a garment from the fabric.

(6) Produce desired creases in the garment.

(7) Subject the garment to textile resin curing conditions.

In each of the above types of procedures, the ultimate curing of the textile resin may be accomplished prior to the manufacture of the garment whereby a good washand-wear fabric having soil release properties is produced.

Procedures of Types I, II and III, as is evident, relate to the process of the present invention being applied to a textile material to afford the textile material soil release and durable press or wash and wear characteristics. Otherwise than above shown, the textile material is treated with an alkali and the various other materials are applied and subjected to textile resin curing conditions, etc., according to the specifications described herein.

The drying temperatures that are insufficient to initiate the catalysis are, of course, dependent upon the particular catalyst being employed. In general, however, the drying step is conducted at a rate of approximately 10 to yards per minute at temperatures ranging from about 225 to 300 F. preferably in a tenter frame. The drying temperature range overlaps to some degree with the curing temperature range set forth below. When drying in the overlapping portion of the drying and curing ranges, it is important that there be no premature curing of the textile resin. Time is the prime variable and when drying the substrate in the higher end of the drying temperature range, care must be taken to avoid heating the substrate for a time sufficient to initiate catalysis that would at least partially cure the textile resin.

Irradiation techniques may be employed according to the process of the present invention when a textile resin having ethylenic unsaturation is applied to the textile material. An insulating core transformer, operated at a potential varying between one hundred thousand electron volts and five hundred thousand electron volts may be successfully used to irradiate the textile material. Such a transformer is commercially available from High Voltage Engineering Corporation, Burlington, Mass. The amount of ionizing irradiation necessary according to the present invention is at least 32 electron volts for each ion pair formed. Thus irradiation of 32 volts and above is effective. Both high energy particle and ionizing irradiation are useful according to the present invention. The preferred dosage of irradiation according to the present invention is in the range of one thousand rads to one hundred megarads, a rad being the amount of high energy irradiation of the type which results in energy absorption of one hundred ergs per gram of absorbing material. More preferably, however, the irradiation dos age ranges from 0.5 to 5 megarads.

Curing of the textile resin is accomplished with mixed synthetic/cellulosic textiles by subjecting the textile material having the textile resin thereon to conditions such that the catalyst initiates a crosslinking reaction between functional groups of the resin and hydroxyl groups of the cellulose in the textile material and converts the resin to the thermoset state. When a 100 percent synthetic fabric is treated, the resin adheres to the material and is converted to a thermoset state. Temperature is the prime mover and generally a temperature in the range of 100 C. to about 300 C. is SUfllClBIlt. The curing medium that supports the necessary temperature may be any substance that is inert to both the fabric and the ingredients applied thereto, e.g., hot air, steam, etc. In the instance Where the textile resin possesses two different types of functional groups, there are actually two curing steps, the first being conducted at a temperature lower than the second and insuflicient to initiate the second type of catalysis, e.g., a first partial curing step to initiate alkaline catalysis and a subsequent curing step to initiate acid catalysis and also convert the resin to the thermoset state.

The duration of the various processing steps varies diversely with the particular ingredients employed. In each situation, however, the treatment time is that necessary to sufiiciently cause reaction of and/ or curing of the textile resin, and preferably, between 0.1 and 30 minutes.

The following examples illustrate preferred embodiments of the present invention but are not intended to restrict the scope of the invention. In the examples, parts and percentages are by Weight. The fabrics prepared in accordance with the procedures set forth in the examples are tested for soil release according to the following procedures. The soil release values are determined by comparison to a set of standards having numerical ratings from 1.0 to 5.0, With 1.0 representing very poor stain removal and 5.0 being virtually complete removal of the stain. The fabrics are stained with mineral oil. After staining the fabric is Washed one time in a Kenmore automatic Washer using one cup of Tide detergent (sold by Procter and Gamble) and a wash water temperature at about 140 F. The fabric is dried for approximately 40 minutes at a temperature of about 160 F. The stains in the dried fabric are compared with the set of standards. The values listed in the tables under the headings and washes represent staining after 5 or 10 normal washings and then a single wash to remove the stain.

EXAMPLE I A fabric made from polyester fibers is treated with a 22% sodium hydroxide solution for a period of about 20 minutes at a temperature of about 70 F. Thereafter the fabric is rinsed with water, acetic acid, water again, and dried. The dried fabric is then treated with a pad bath containing 4% solids of an emulsion copolymer comprising 70% ethyl acrylate and 30% acrylic acid. The above bath is padded onto the fabric to provide about 50% wet pickup, and the fabric is then dried at a temperature of about 260 F. until the moisture content of the fabric is reduced to approximately 5%.

The resulting fabric is tested to determine its soil release. The results of the tests are reported in Table I.

EXAMPLE II The procedure of this example is the same as that of Example I, except the fabric is treated only with the sodium hydroxide solution, rinsed and dried. Tests on the fabric show the results set forth in Table I.

EXAMPLE III The procedure of this example is the same as that of Example I, except the treatment with the sodium hydroxide solution is omitted. Tests on the fabric show the results set forth in Table I.

14 TABLE I Example: Soil release I 4.1 II 1.0 III 3.2 Control 1.0

EXAMPLE IV The procedure of this example is the same as that of Example I except that the time of the sodium hydroxide treatment was decreased to 10 minutes. The results are reported in Table II.

EXAMPLE V The procedure of this example is the same as that of Example I except that the time of the sodium hydroxide treatment was decreased to 5 minutes. The results are reported in Table II.

EXAMPLE VI The procedure of this example is the same as that of Example I except that the time of the sodium hydroxide treatment was decreased to 1 minute. The results are reported in Table II.

TABLE II Example: Soil release IV 3.8 V 3.9 VI 3.7 Control 10 EXAMPLE VII A Dacron/ cotton (65/35) fabric is treated with a 5% sodium hydroxide solution in a steam atmosphere at 212 F. for about 15 minutes. Thereafter the fabric is rinsed with Water, acetic acid, water again, and dried. A mixture of 24% dihydroxy diinethylol ethylene urea (50% solution), 2% zinc nitrate (Zn(NO -6H O) and 10% of the emulsion copolymer used in Example I is applied to the fabric to provide about a 50% wet pickup. The fabric is then dried at a temperature of about 260 F., and tested to determine its soil release characteristics both as received and after laundering. The results of the tests are reported in Table III.

EXAMPLE VIII The procedure of this example is the same as that of Example VII except that the sodium hydroxide treatment is for a period of 30 minutes. The test results are reported in Table III.

EXAMPLE IX The procedure of this example is the same as that of Example VII except that the concentration of the sodium hydroxide solution is reduced to 3%. Tests on the fabric show the results set forth in Table III.

EXAMPLE X The procedure of this example is the same as that of Example VIII except that the concentration of the sodium hydroxide solution is reduced to 3%. The test results are set forth in Table HI.

EXAMPLE XI EXAMPLE XII The procedure of this example is the same as that of Example VII except that the concentration of the sodium hydroxide solution is reduced to 2%. The test results are set forth in Table III.

15 EXAMPLE XIII The procedure of this example is the same as that of Example VII except that the concentration of the sodium hydroxide solution is reduced to 1%. Tests on the fabric show the results set forth in Table III.

EXAMPLE XIV The procedure of this example is the same as that of Example VIII except that the concentration of the sodium hydroxide solution is reduced to 1%. The test results are set forth in Table III.

EXAMPLE XV The procedure of this example is the same as that of Example VII except that the concentration of the sodium hydroxide solution is reduced to 0.5%. Tests on the fabric shoW the results set forth in Table III.

EXAMPLE XVI The procedure of this example is the same as that of Example VIII except that the concentration of the sodium hydroxide solution is reduced to 0.5%. The soil release results set forth in Table III.

EXAMPLE XVII TABLE III Soil release As received I wash Example 5 washts 1 With copolymer.

EXAMPLE XVIII A Dacron/cotton (65/35) fabric is immersed in a 1% sodium hydroxide solution maintained at a temperature of about 160 F., rinsed with water, acetic acid and water again and then padded with a solution containing 20% solids of a carbamate textile resin sold under the trade name Stanset C35 by Standard Chemical Products Co., 4% of the emulsion copolymer employed in Example I, 6% magnesium chloride catalyst and 2.3% ethoxylated alkyl phenol.

The fabric is then cured at a temperature of about 325 F. for about 90 seconds to determine its soil release both initially and after repeated laundering.

The tests results are reported in Table IV.

EXAMPLE XIX The procedure of this example is the same as that of Example XVIII except the concentration of sodium hydroxide was increased to 3% and 0.3% orthophenyl phenol was mixed with the sodium hydroxide. The results of the tests are set forth in Table IV.

With resin and copolymer.

16 EXAMPLE xx The procedure of this example is the same as that of Example I except that the acrylic acid-ethyl acrylate copolymer is replaced with each of the following copolymers with results similar to those of Example I:

Butyl acrylate:acrylic acid (12: 88)

Butyl acrylate: acrylic acid (30:70)

Butyl acrylate:acrylic acid (:20)

Butyl acrylate:acrylic acid (88: 12)

Ethyl acrylatezmethacrylic acid (70:30)

Ethyl acrylate:itaconic acid (70:30)

Methyl methacrylate:acrylic acid (70:30) Acrylamide acrylic acid (10:90)

Ethyl acrylatezacrylic acid:acrylamide (50:38:12) Ethyl acrylatezacrylic acidzaciylamide (65 :30:5)

The above example show that the process of the present invention provides improved soil release characteristics in fabrics formed with synthetic polymeric fibers. It will be seen from the examples that omitting the treatment with the alkali results in a significant loss of soil release. For example, see the comparison in Table I between Example I (the process of the invention) and the other examples.

The above description and examples show that the process of the present invention provides improved soil release characteristics in fabrics formed from synthetic polymeric fibers. Furthermore, the process of the invention also provides improved soil release with durable press and/or wash and wear fabrics.

Having thus disclosed the invention, what is claimed 1. A process for imparting soil release characteristics to a synthetic polymeric textile material which comprises subjecting the textile material to an alkali metal hydroxide or salt, applying thereto a liquid composition comprising a soil release synthetic acid emulsion copolymer having a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1, and drying the synthetic acid copolymer treated textile material.

2. The process as defined in claim 1 wherein the synthetic acid copolymer treated textile material is heated at a temperature in the range of about C. to 300 C.

3. The process as defined in claim 1 wherein the textile material is a polyester.

4. The process as defined in claim 1 wherein the soil release copolymer is prepared by polymerizing a monomeric mixture comprising an acrylic ester and an acrylic acid.

5. A process for imparting soil release characteristics to synthetic polymeric textile material which comprises subjecting the textile material to an alkali metal hydroxide or salt; applying thereto a textile resin, a latent acid or base acting textile resin catalyst and a soil release synthetic acid emulsion copolymer having a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1; and subjecting said resin treated textile material to a temperature between about 100 and 300 C.

6. The process as defined in claim 5 wherein the textile resin catalyst is selected from the group consisting of zinc nitrate and magnesium chloride.

7. The process as defined in claim 5 wherein the soil release copolymer is prepared by polymerizing a monomeric mixture comprising an acrylic ester and an acrylic acid.

8. A process as defined in claim 5 wherein the textile resin catalyst is selected from the group consisting of metal salts and amino salts.

9. The process as defined in claim 5 wherein the textile resin is selected from the group consisting of acrylamides and ethylene ureas.

10. The process as defined in claim 5 wherein the textile resin is selected from the group consisting of N-methylol acrylamide and dihydroxydimethylol ethylene urea.

11. The process as defined in claim 5 wherein the soil release copolymer is prepared by polymerizing a mono- I 7 meric mixture comprising about 10 to 80 parts of an acrylic ester and about 20 to 90 parts of an acrylic acid. 12. A process for imparting soil release and durable press characteristics to a textile material including a blend comprising cellulosic and synthetic polymeric fibers, which comprises subjecting the textile material to an alkali metal hydroxide or salt; applying thereto an aminoplast textile resin, a latent acid or base acting textile resin catalyst, and a synthetic acid copolymer, said acid copolymer comprising at least 10 weight percent acid calculated as acrylic acid and having a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1; and subjecting said textile material to a temperature between about 100 and 300 C. whereby the textile resin is crosslinked to the textile material.

13. The process as defined in claim 5 wherein the acid copolymer is prepared by polymerizing a monomeric mixture comprising about to 80 parts of an acrylic ester and about 20 to 90 parts of an acrylic acid.

14. A process for imparting soil release and durable press characteristics to a textile material including a blend comprising cellulosic and synthetic polymeric fibers; subjecting the textile material to an alkali metal hydroxide; applying thereto an unsaturated aminoplast textile resin, a latent acid or base acting textile resin catalyst, and a synthetic acid copolymer, said acid copolymer comprising at least 10 weight percent acid calculated as acrylic acid and having a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1; drying the resin treated textile material at a temperature in the range of about 225 F. to 300 F. for a time insufficient to initiate crosslinking between the textile resin and the cellulose molecules of the textile material; subjecting the dried resin treated textile material to irradiation; and subsequently curing the textile resin.

15. The process as defined in claim 14 wherein the textile resin is N-methylol acrylamide.

16. A process for imparting soil release and durable press characteristics to a polyester/cotton blend textile material which comprises:

(a) subjecting the textile material to an alkali metal hydroxide;

(b) padding onto the textile material an unsaturated arninoplast textile resin, a latent acid or base acting textile resin catalyst, and a synthetic acid copolymer, said acid copolymer comprising at least 10 weight percent acid calculated as acrylic acid and having a carbon atom to acid group ratio in the repeat group in the range of 2:1 to 30:1;

(c) drying the resin treated textile material at a temperature from about 225 F. to 300 F. for a time insufficient to activate the textile resin catalyst;

(d) subjecting the dried textile material to irradiation in the amount of about 0.5 to 5 megarads; and

(e) heating the irradiated resin treated textile material at a temperature in the range of about 100 C. to 300 C. for a time sufficient to cure the textile resin.

17. The process as defined in claim 16 wherein the textile resin is N-methylol acrylamide.

18. The process as defined in claim 16 wherein the acid copolymer is prepared by polymerizing a monomeric mixture comprising about 10 to parts of an acrylic ester and about 20 to parts of an acrylic acid.

References Cited UNITED STATES PATENTS 1,818,466 r 8/1931 Dreyfus et al.

2,03 6,424 4/ 1936 Malm 1l7-56 X 2,314,968 3/1943 Bestian et al 8-115.6 X 2,724,664 11/1955 Gagarine et al 11756 X 2,820,719 1/1958 Trusler et al 117--56 X 2,944,921 7/ 1960 Groves et al.

2,986,507 5/1961 Steck 117-9331 2,998,329 8/1961 SOulsh et al l1793.31 2,999,056 9/1961 Tanner 117-93.31 X 3,090,704 5/1963 Collins et al 117-138.8 3,092,512 6/1963 Magat et al 11793.31 X 3,125,405 3/ 1964 Gordon 8-1 16.3 3,152,920 10/1964 Caldwell et a1 l17138.8 3,183,054 5/1965 Fischer et al. 8116.3 X 3,216,780 11/1965 Landells et al 8116.3 3,236,685 2/1966 Caldwell et al 117138.8 3,246,946 4/1966 G ordor 8-116.3 3,402,061 9/1968 Faria et al 117138.8 X 3,405,003 10/1968 DePaolo et al. 1l7-13 8.8 X

FOREIGN PATENTS 830,778 3/ 1960 Great Britain.

WILLIAM D. MARTIN, Primary Examiner M. R. LUSIGNAN, Assistant Examiner U.S. C1.X.R.

Patent No. 3, 535, 141 m October 20, 1970 Inve t fl Francis W. Marco It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the title, change "SAIL" to --SOIL--. Column 2, line 18 change "hereafter" to --hereinafter--. Column 6, formula VIII, line 30, that portion of the formula reading "-CR -CHR should read -CR -CHR Column 6, formula X, that portion of the formula reading "R -NC" should read R -HC. Column 6, line 57 change "retentions" to --retention--. Column 7, line 39 after "mildly" insert --alkaline--. Column 8, line 69 change "coplymer" to --copolymer--. Column 10, line 74 after "weight" insert --percent--. Column 16, line 18 change example" to --examples-. Column 17, line 16, Claim 13, change '5" to lZ-- Signed and sealed this 22nd day of June 1971.

(SEAL) Attest:

EDWARD M.F'LETCHE3R WILLIAM E. SCHUYLER, J'R. Attesting Officer Commissioner of Patents 

